Methods for localization and visualization of electrodes and probes in the brain using anatomical mesh models

Abstract

This invention relates generally to methods for localization and visualization of implanted electrodes and penetrating probes in the brain in 3D space with consideration of functional brain anatomy. Particularly, this invention relates to precise and sophisticated methods of localizing and visualizing implanted electrodes to the cortical surface and/or topological volumes of a patient's brain using 3D modeling, and more particularly to methods of accurately mapping implanted electrodes to the cortical topology and/or associated topological volumes of a patient's brain, such as, for example, by utilizing recursive grid partitioning on a manipulable virtual replicate of a patient's brain. This invention further relates to methods of surgical intervention utilizing accurate cortical surface modeling and/or topological volume modeling of a patient's brain for targeted placement of electrodes and/or utilization thereof for surgical intervention in the placement of catheters or other probes into it.

The invention claimed is: 
     
       1. A method for localization of implanted electrodes in a brain of a subject, said method comprising:
 performing an anatomical scan of said brain; 
 generating a three-dimensional (3D) model of said brain using said anatomical scan, said 3D model comprising cortical topological features; 
 performing a first direct imaging of at least a portion of a pial surface of said brain; 
 identifying at least one anatomical landmark on said pial surface from said first direct imaging and performing a correlation of said at least one anatomical landmark to said 3D model; 
 implanting at least one reference electrode onto said at least a portion of said pial surface; 
 performing a second direct imaging of said at least a portion of said pial surface after said implanting; 
 visually localizing said at least one reference electrode on said 3D model using said correlation of said at least one anatomical landmark; and 
 localizing a position of said at least one reference electrode on said pial surface of said brain of said subject on said 3D model of said brain generated using said anatomical scan; 
 recording electrical activity from said at least one reference electrode; 
 generating a recording zone for said at least one reference electrode by geodesic expansion along said cortical topological features in said 3D model centered on said at least one reference; and 
 visualizing said electrical activity by projecting onto said recording zone on said 3D model to illustrate a potential region of said brain contributing to said electrical activity. 
 
     
     
       2. The method of  claim 1  wherein said first and second direct imaging comprises an imaging method selected from the group consisting of digital photography and analog photography. 
     
     
       3. The method of  claim 1  wherein said anatomical scan comprises anatomical magnetic resonance imaging (aMRI). 
     
     
       4. The method of  claim 1 , further comprising implanting an array of electrodes onto said at least a portion of said pial surface prior to said second direct imaging, wherein said at least one reference electrode comprises a member of said array of electrodes. 
     
     
       5. The method of  claim 4 , further comprising visually localizing said array of electrodes on said 3D model using said correlation of said at least one anatomical landmark. 
     
     
       6. The method of  claim 5 , wherein said array of electrodes are visually localized by a human medical practitioner or automatically by a computer. 
     
     
       7. The method of  claim 4 , further comprising recursively localizing said array of electrodes on said 3D model by contouring said array of electrodes to said cortical topological features in said 3D model relative to said at least one localized reference electrode, said array of electrodes comprising a grid which conforms to said pial surface in situ with said electrodes placed at known positions relative to said at least one reference electrode. 
     
     
       8. The method of  claim 7 , wherein said array of electrodes comprises a rectangular grid with at least four reference electrodes arranged at corners of said rectangular grid. 
     
     
       9. The method of  claim 8 , wherein said array of electrodes extends beyond said craniotomy boundary. 
     
     
       10. The method of  claim 7  wherein said contouring of said array of electrodes to said cortical topological features comprises contouring said array of electrodes to a smoothed 3D model which omits sulcal anatomy and which is aligned with said 3D model. 
     
     
       11. The method of  claim 1 , further comprising generating a lissencephalic view of said 3D model by flattening a difference between depths of sulci and peaks of gyri while preserving the overall shape of said brain and projecting said recording zone onto said lissencephalic view of said 3D model. 
     
     
       12. The method of  claim 1 , further comprising highlighting said cortical topological features in said lissencephalic view to generate a parcellated lissencephalic view with different visual coding of said 3D model and projecting said recording zone onto said parcellated lissencephalic view of said 3D model. 
     
     
       13. The method of  claim 1 , further comprising highlighting said cortical topological features to generate a parcellated view with different visual coding in said 3D model and projecting said recording zone onto said parcellated view of said 3D model. 
     
     
       14. The method of  claim 1 , further comprising highlighting regions of said brain not being recorded by said at least one reference electrode based on an outer boundaries of said recording zone of said implanted electrode. 
     
     
       15. The method of  claim 1 , wherein said projecting of said electrical activity comprises applying an electrical signal decay function to said geodesic expansion. 
     
     
       16. The method of  claim 1 , wherein said implanting of said at least one reference electrode occurs prior to said second direct imaging.